Study on the Stability of Coal Pillars Under the Disturbance of Repeated Mining in a Double-Roadway Layout System

Abstract

The double-roadway layout system, which is extensively applied in large mines, has the potential to significantly balance excavation-mining and improve mine ventilation and transportation capacity. However, the coal pillar in the double-roadway layout system is easily destabilized due to the disturbance of repeated mining, which has a significant impact on the safety and reliability of coal mines. This paper takes the coal pillar and its supporting structure of the double-roadway layout system as the research object, establishes a UDEC trigon numerical calculation model, and systematically corrects the input parameters, while explaining the excavation method of roadways and the simulation method of the supporting structure element. The numerical simulation results show that under the conventional support intensity conditions, the internal damage of the coal pillar during the excavation period is about 20%, while the internal damage to the coal pillar develops to 55% throughout the first-panel mining. During the disturbance of repeated mining, the damage in the coal pillar increased to 90%, and the coal pillar was already in a state of failure. Under the combined control of rock bolts and counter-pulled anchor cables, the coal pillar damage does not change significantly during the excavation and first-panel mining. During the disturbance of repeated mining, the damage of the coal pillar is reduced to 63%. There is a certain low damage area in the coal pillar, which can ensure the stability of the coal pillar and its supporting structure as a whole. Furthermore, the on-site monitoring results show that the maximum value of the floor-to-roof and rib-to-rib convergence of a W1310 tailgate during the repeated mining disturbance stage is 730 and 620 mm, respectively. The findings of this study give an approach to—as well as estimated values for the design of, including its “small structure” control technical parameters—the double-roadway layout system.

Evolution Laws of Stress–Energy and Progressive Damage Mechanisms of Surrounding Rock Induced by Mining Disturbance

“…Guo [18] et al have analyzed the spatio-temporal rotation characteristics of the principal stress in the surrounding rock of the roadway under mining disturbance and optimized the layout scheme and blasting parameters of the blasting pressure relief hole according to the principal stress rotation characteristics under the dual influence of mine seismic disturbance and goaf. Liu [19] et al believed that under the effect of repeated mining disturbance, the coal pillar failure degree reached 90%, which was already in the state of failure. Qi [20] et al comprehensively adopted theoretical analysis and numerical simulation to reveal the failure mechanism of surrounding rock under intense mining disturbance of thick coal seam and verified it through field measurement results.…”

Failure mechanism and support system of roofs in advance areas affected by mining under the condition of soft rock stratum

“…Thus, they presented the corresponding control technology. Liu et al (2021) studied the stress evolution and surrounding rock failure of roadways and coal pillars under the influence of repeated mining in a double-roadway layout system through UDEC (Universal Distinct Element Code) numerical simulation software. Zhu et al (2022) analyzed the stress distribution law caused by mining under different roof strengths through FLAC 3D (Fast Lagrangian Analysis of Continua) and obtained the influence area range of the working face pressure.…”

An Investigation Into the Mechanism of Rock Bursts in Mines for Tunnel-Cut Isolated Areas with Multiple Stress Fields

“…Another accident occurred on February 22, 2020, in the Xinjulong mine in Shandong, resulting in four deaths and the loss of 18 million RMB. In the aforementioned incidents, the tunnelcut coal areas were subjected to the lateral abutment pressure of the goafs and mining stress in the working face, which affected the associated geological structures and accumulated a significant amount of strain energy in the areas in question (Cui et al, 2021;Liu et al, 2021;Tian et al, 2021;Wu et al, 2021). Therefore, failure of overlying strata readily occurred over a wide area, resulting in rock bursts.…”

“…Several studies have been conducted to prevent the occurrence of a rockburst in an isolated coal pocket or pillar (Adoko et al, 2013;Xu et al, 2017;Zhou et al, 2018;Pinzani and Coli, 2011;Zhang et al, 2021b;Liu et al, 2021), but little research has focused on the types of rock bursts that can occur in tunnel-cut coal. This study focuses on several incidents that have occurred in Shaanxi Province.…”